1. Technical Field
The invention relates to a windscreen wiper device comprising an elastic, elongated carrier element, as well as an elongated wiper blade of a flexible material, which can be placed in abutment with a windscreen to be wiped, which wiper blade includes at least one longitudinal groove, in which groove a longitudinal strip of the carrier element is disposed, which windscreen wiper device comprises a connecting device for an oscillating wiper arm, as well as a spoiler. Such a spoiler is also called an “air deflector”.
2. Related Art
Such a windscreen wiper device is generally known. The prior art windscreen wiper device is in particular designed as a “yokeless” wiper device, wherein use is no longer made of several yokes pivotally connected to each other, but wherein the wiper blade is biassed by the carrier element, as a result of which it exhibits a specific curvature. The spoiler and the wiper blade of the known windscreen wiper device are made in one piece.
Windscreen wiper devices actually used on cars fined with windscreens exhibiting some degree of curvature are sometimes subjected to a lifting effect at high speeds, which prevents the windscreen from being wiped correctly. This lifting effect is due to the following aerodynamic phenomenon. Streams of air along the car tend to escape vertically upwards along the axis of the car. Near the sides of the curved windscreen, however, the streams of air tend to pass horizontally along the sides. These streams of air create, mainly in the zones in which the windscreen wiper device meets them perpendicularly, a reduced pressure above the windscreen wiper device and an increased pressure between the windscreen and the windscreen wiper device. The resulting pressure, in spite of the mechanical pressure applied by the arm of the windscreen wiper device, causes the latter to lift away towards the front of the windscreen, thereby deteriorating the wiping pattern at higher driving speeds. A spoiler is often used to suppress the lifting effect.
A disadvantage of the known windscreen wiper device is that a specific wiper blade equipped with an asymmetric spoiler has to be designed and manufactured for an oscillating arm at the drivers side of a vehicle and for an oscillating arm at the passengers side of the vehicle. Obviously this requires the use of complex machinery, tools, with all the expenses involved, A further drawback is that mutually differing wiper blades with asymmetric spoilers for each type of oscillating arm (that is at the drives side or at the passenger side) require much space for storage both in a warehouse and in a shop. Still a further disadvantage is that a wiper blade equipped with an asymmetric spoiler meant to be mounted on an oscillating arm at the drivers side of a vehicle is often actually mounted on an oscillating arm at the passengers side of the vehicle, while such wiper blade equipped with an asymmetric spoiler meant to be mounted on an oscillating arm at the passenger side of a vehicle is often actually mounted on an oscillating arm at the drivers side of the vehicle. Such a reversed mounting of these wiper blades seriously affect the wiping qualities thereof particularly at high speeds, with all negative consequences involved.